Access point multi-level transmission power and protocol control based on the exchange of characteristics

ABSTRACT

A wireless access point and multiple wireless terminals exchange utilization, status, mobility and reception characteristics. Each wireless terminal generates reception characteristics based on transmissions received from the wireless access point and from other devices in the network. In one operating mode, the characteristics gathered by the wireless devices are forwarded to the wireless access point, and, based on all received characteristics, the wireless access point selects its own transmission power for different types of the transmission. In another mode, all characteristics are exchanged between every wireless terminal and the access point so that each can independently or cooperatively make transmission power control decisions. In a further mode, the wireless access point adjusts protocol parameters based on an assessment of the characteristics received from the client devices. The utilization, status, mobility, and reception characteristics include received signal strength, error rates, estimated battery life, availability of unlimited power, active versus sleep mode ratios, anticipated bandwidth utilization, coding schemes available, deterministic/non-deterministic requirements, encryption and security requirements, quality of service requirements, position, velocity, stationary status, etc. Gathering of such characteristics involves both retrieval of preset parameters from memory and generating parameters based on received transmissions (including test packets).

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 120 as acontinuation of the pending application having Ser. No. 11/398,930,entitled ACCESS POINT MULTI-LEVEL TRANSMISSION POWER AND PROTOCOLCONTROL BASED ON THE EXCHANGE OF CHARACTERISTICS, filed on Apr. 6, 2006,the contents of which are incorporated herein by reference thereto.

TECHNICAL FIELD OF THE INVENTION

This invention relates generally to wireless communication systems, andmore particularly to transmit power control and protocol control ofwireless communication devices within such wireless communicationsystems.

BACKGROUND OF THE INVENTION

Wireless communication systems are known to support wirelesscommunications between wireless communication devices affiliated withthe system. Such wireless communication systems range from nationaland/or international cellular telephone systems to point-to-pointin-home wireless networks. Each type of wireless communication system isconstructed, and hence operates, in accordance with one or morestandards. Such wireless communication standards include, but are notlimited to IEEE 802.11, Bluetooth, advanced mobile phone services(AMPS), digital AMPS, global system for mobile communications (GSM),code division multiple access (CDMA), wireless application protocols(WAP), local multi-point distribution services (LMDS), multi-channelmulti-point distribution systems (MMDS), and/or variations thereof.

An IEEE 802.11 compliant wireless communication system includes aplurality of client devices (e.g., laptops, personal computers, personaldigital assistants, etc., coupled to a station) that communicate over awireless link with one or more access points. The transmitting device(e.g., a client device or access point) transmits at a fixed power levelregardless of the distance between the transmitting device and atargeted device (e.g., station or access point). Typically, the closerthe transmitting device is to the targeted device, the less error therewill be in the reception of the transmitted signal. However, as isgenerally understood in the art, wireless transmissions may include someerror and still provide an accurate transmission. Thus, transmitting atpower levels that provide too few errors is energy inefficient.

As is also generally understood in the art, many wireless communicationssystems employ a carrier-sense multiple access (CSMA) protocol thatallows multiple communication devices to share the same radio spectrum.Before a wireless communication device transmits, it “listens” to thewireless link to determine if the spectrum is in use by another stationto avoid a potential data collision. At lower received power levels,this protocol can lead to a hidden terminal problem when two devices,generally spaced far apart, are both trying to communication with athird device in the middle. While the device in the middle can “hear”the two devices on the periphery, these two devices cannot hear oneanother—potentially creating data collisions with simultaneoustransmissions destined for the middle device.

Further limitations and disadvantages of conventional and traditionalapproaches will become apparent to one of ordinary skill in the artthrough comparison of such systems with the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 presents a pictorial representation of a wireless network 10 inaccordance with an embodiment of the present invention.

FIG. 2 presents a timing diagram of transmissions by the access point110 and the client devices 121 and 123 in accordance with an embodimentof the present invention.

FIG. 3 presents a pictorial representation of a wireless network 10 thatshows examples of client devices and various modes of connection betweenaccess points and packet switched backbone network 101 in accordancewith an embodiment of the present invention.

FIG. 4 presents a block diagram representation of an access point 300that can be used in wireless network 10 in accordance with an embodimentof the present invention.

FIG. 5 presents a block diagram representation of a client device 400that can be used in wireless network 10 in accordance with an embodimentof the present invention.

FIG. 6 presents a block diagram representation of a client device 400′with optional GPS circuitry 416 and power source regulation circuitry420 in accordance with an embodiment of the present invention.

FIG. 7 presents a block diagram representation of an access point 300′with optional ΔP assessment application 225 in accordance with anembodiment of the present invention.

FIG. 8 presents a pictorial representation of a wireless network 10 inaccordance with an embodiment of the present invention that provides amanagement application 225 in one of a plurality of terminals.

FIG. 9 presents a flowchart representation of a method that can be usedin a terminal, access point and/or an integrated circuit in accordancewith an embodiment of the present invention.

FIG. 10 presents a flowchart representation of a method that can be usedin a terminal, client device and/or an integrated circuit in accordancewith an embodiment of the present invention.

SUMMARY OF THE INVENTION

The present invention sets forth a wireless network, access point,client device, integrated circuit and methods that determinetransmission power and protocol parameters based on receivedcharacteristics substantially as shown in and/or described in connectionwith at least one of the figures, as set forth more completely in theclaims that follow.

DETAILED DESCRIPTION

FIG. 1 presents a pictorial representation of a wireless network 10 inaccordance with an embodiment of the present invention. A wirelessnetwork 10 includes an access point 110 that is coupled to packetswitched backbone network 101. The access point 110 managescommunication flow destined for and originating from each of clientdevices 121, 123, 125 and 127 over a wireless network 10. Via the accesspoint 110, each of the client devices 121, 123, 125 and 127 can accessservice provider network 105 and Internet 103 to, for example, surfweb-sites, download audio and/or video programming, send and receivemessages such as text messages, voice message and multimedia messages,access broadcast, stored or streaming audio, video or other multimediacontent, play games, send and receive telephone calls, and perform anyother activities, provided directly by access point 110 or indirectlythrough packet switched backbone network 101.

The access point 110 is capable of transmitting high power transmissions99 and reduced power level transmissions 98 at one or more reduced powerlevels, depending on the type of transmission, the characteristics ofthe particular client device to which the transmission is addressed andthe characteristics of the other client devices that are associated withthe access point 110. The access point 110 includes a managementapplication 225, and each client devices 121, 123, 125 and 127 includesa client assessment application 404. The management application 225 andthe client assessment applications 404 of each of the client devices121, 123, 125 and 127 operate to select adequate transmission powersettings that conserve battery power and limit unnecessaryelectromagnetic radiation. For example, as directed by a clientassessment application 404, the client device 121 assesses transmissionsfrom the access point 110 and the client devices 123, 125 and 127. Theclient device 121 generates reception characteristics based on theassessment. The client device 121 also gathers local status information,anticipated bandwidth utilization characteristics and mobilityinformation, and, based thereon, generates status characteristics,utilization characteristics, and mobility characteristics. The clientdevice 121 delivers the reception characteristics, statuscharacteristics, utilization characteristics and mobilitycharacteristics to the access point 110 for use by the managementapplication 225. According to their client assessment applications 404,the other of the client devices 123, 125 and 127 similarly gather anddeliver their local status characteristics, utilization characteristicsand mobility characteristics along with reception characteristicsrelating to others of the client devices and the access point 110.

The access point 110, in accordance with the management application 225,also generates its own reception characteristics and utilizationcharacteristics. The management application 225 adjusts the accesspoint's transmission power and controls the transmission power of eachof the client devices 121, 123, 125 and 127 based on: 1) the receptioncharacteristics received from each of the client devices 121, 123, 125and 127 regarding others of the client devices and the access point; 2)locally generated reception characteristics and utilizationcharacteristics regarding each of the client devices 121, 123, 125 and127; 3) status characteristics from each of the client devices 121, 123,125 and 127; 4) mobility characteristics from each of the client devices121, 123, 125 and 127; and 5) utilization characteristics generated byeach of the client devices 121, 123, 125 and 127. The access point 110achieves such control by causing the access point 110 to deliver controlinstructions to each of the client devices 121, 123, 125 and 127 via thewireless network. Each of the client devices 121, 123, 125 and 127respond to the control instructions by adjusting its transmit power.Such overall control takes advantage of particular, currentcircumstances, including current operational status, relative positionsand properties of any the network nodes (e.g., the access point 110 andthe client devices 121, 123, 125 and 127).

As used herein, “reception characteristics” includes any data, generatedbased on received wireless transmissions, that rates or can be used torate the quality, accuracy or strength of such received wirelesstransmissions. For example, reception characteristics might include anyone or more of a Received Signal Strength Indication (RSSI), bit/packeterror, current/historical error rates, multipath interferenceindications, Signal to Noise Ratio (SNR), fading indications, etc.

Status characteristics includes any data relating to an underlyingdevice's prior, current or anticipated readiness, abilities or capacityfor participating on the wireless network. Status characteristicsinclude, for example, the amount of power available, such as whetheralternating current (AC) power is available or only battery power, and,if battery power, anticipated battery life at various transmission powerlevels and at various levels of participation, etc. Statuscharacteristics also include whether a device is currently “sleeping” orinactive or in a low power idle state. It may also include historicalinformation anticipating the current status duration and anticipatedstatus characteristics changes. Status characteristics may also includestatus information relating to each underlying communication softwareapplication that runs on a client device. For example, on a singleclient device two communication applications might be present with onein an inactive state and the other actively communicating. Statuscharacteristics would identify such activity and inactivity.

Utilization characteristics include any parameter that indicates aprior, current or anticipated bandwidth requirement, usage or usagecharacteristic. Utilization characteristics might include anticipatedQoS (Quality of Service) requirements, upstream/downstream bandwidthusage, bandwidth usage characteristics, idle versus active statuscharacteristics, underlying data/media types (e.g., voice, video,images, files, database data/commands, etc.) and correspondingrequirements, etc.

Mobility characteristics include for example indications as to whetherthe underlying device is: 1) permanently stationary, e.g., a desktopclient computer, game console, television, set top box or server; 2)capable of mobility, e.g., a cell phone or mobile VoIP (Voice overInternet Protocol) phone, PDA (Personal Digital Assistant), and palm,laptop or pad computer; and 3) currently moving, e.g., any one or moreof current position and direction, velocity and accelerationinformation.

In operation, the access point 110 is capable of transmitting at aselected power level that is based on factors such as the type oftransmission, the reception characteristics, status characteristics,utilization characteristics, mobility characteristics, and theparticular target device for the transmission. For instance, accesspoint 110 can transmit periodic beacons at a high power level thatinclude information relating to the access point 110 and the packetswitched backbone network 101 such as a service set identifier (SSID)and network name. These beacons are used to support new associationswith client devices 121, 123, 125 and 127 that enter the proximity ofaccess point 110 or that otherwise become active within this proximity.Reception characteristics relating to how well the client devices 121,123, 125 and 127 receive these beacon transmissions can be generated bythe client assessment applications 404 of these client devices andtransmitted back to the access point 110. In response, managementapplication 225 determines a customized power level for the access pointto transmit to each client device 121, 123, 125, and 127 that may bereduced from the maximum power output, but that provides sufficientpower to be received by that particular client device. In addition,management application 225 determines an intermediate power level thatis sufficient to be received by all of the client devices 121, 123, 125and 127. Specific packets, such as all acknowledgements (ACKs), everyother ACK, every nth ACK etc., all data packets, occasional datapackets, etc. are transmitted by the access point 110 at theintermediate power level that will reach all of the client devices 121,123, 125 and 127, with the remaining packets transmitted at the powerlevel that is customized for the particular client device 121, 123, 125or 127 to which the packets are addressed.

Reducing the transmitted power of the access point, and of the clientdevices themselves, reduces the power consumption of thesedevices—potentially extending the life of the devices and the batterylife for devices that are battery powered. In addition, the resultingwireless network 10 is more “transmission friendly” to neighboringnetworks. The transmission of beacons at high power promotes theassociation of new client devices to wireless network 10. Thetransmission of packets addressed to a particular client device 121,123, 125 or 127, at a customized power level enhances the powerefficiency of the network. The transmission of selected packets at theintermediate power level, that will reach all of the client devices 121,123, 125 and 127 that are associated with access point 110, helps reducehidden terminal problems by letting other client devices know that adevice is transmitting.

By way of example, the access point 110 may transmit at ten discretepower levels at 1 dB increments, say 10 through 1, with 10 correspondingto the full power transmission, 9 corresponding to a 1 dB reduction intransmitted power, 8 corresponding to a 2 dB reduction in power, etc.Based on reception characteristics received from client devices 121,123, 125, and 127, management application 225 of access point 110determines the following power levels are sufficient to be received byeach client device:

Client Device Power level 121 5 123 6 125 8 127 6Access point 110 transmits beacons at a power level of 10. Access point110 transmits every other ACK with a power level of 8, sufficient to bereceived by each client device 121, 123, 125 and 127. Other packets fromaccess point 110 are transmitted at the power level assigned to theaddressee client device. Packets addressed to client devices 123 or 127are transmitted at power level 6, packets addressed to client device 121are transmitted at power level 5, packets addressed to client device 125are transmitted at power level 8.

While the reception characteristics are described above as generated inresponse to access point beacons, the reception characteristics can alsobe collected by a given one of the client devices 121, 123, 125 and 127through a test mode and through “sniffing”. In the test mode, the accesspoint 110 directs each of the client devices to respond with receptioncharacteristics in response to transmissions from the access point 110at one or more transmission power levels. Also, in the test mode, theaccess point 110 directs one of the client devices 121, 123, 125 and 127to transmit at one or more selected power levels and all others togenerate and deliver reception characteristics in response. The accesspoint 110 may similarly direct each of the others of the client devices121, 123, 125 and 127 to send the test transmissions and correspondinglyhave the others respond by generating reception characteristics. Testingcan be conducted periodically or whenever conditions indicate thattransmission power adjustments may be needed. Devices that are mobilemay undergo testing more often than those that are stationary.Collecting reception characteristics through sniffing involves a clientdevice listening to ordinary (not test) transmissions from and to theaccess point 110. The access point 110 may request receptioncharacteristics based on such sniffing or may be delivered sameoccasionally or periodically (e.g., as significant changes are detected)and without request by each client device. Similarly, without request,status characteristics, utilization characteristics and mobilitycharacteristics may be reported as significant changes therein occur bya client device to the access point 110.

Further, while the selected power levels used by access point 110 totransmit to each client device are described above as being determinedbased on reception characteristics, management application 225 canlikewise use status characteristics, utilization characteristics andmobility characteristics and with periodic updates thereto, to determinethe customized power levels for transmission to each client device 121,123, 125, and 127 and the intermediate power level that will reach allclient devices. For example, the client device 123 generates receptioncharacteristics from transmissions between the client device 121 and theaccess point 110. The client device 123 delivers the receptioncharacteristics generated to the access point 110. The client device123, a stationary desktop computer, has access to AC power, and has afull-duplex, video streaming application running in an activecommunication state which requires significant bandwidth and QoS. Theclient device 123 communicates such corresponding statuscharacteristics, utilization characteristics and mobilitycharacteristics to the access point 110. The client device 125, abattery powered device with significant remaining battery life, isoperating with little communication traffic either direction. The clientdevice 125 generates reception characteristics for all communicationexchanges. The client devices 121 and 127, portable communicationdevices with minimal power resources, both have one or morecommunication applications active that require light but continuousbandwidth demands. Both also generate reception characteristicsregarding communication flowing in all directions. Such receptioncharacteristics and underlying status characteristics, utilizationcharacteristics and mobility characteristics are communicated to theaccess point 110. The management application 225 of the access point 110considers all such received communications, and for example, may operateat the higher overall transmission power with protocol supported QoS andpriority when transmitting to client device 123. When transmitting atthe intermediate power level, all of the other client devices shouldreceive the transmissions and attempt to avoid simultaneous, interferingtransmissions. Further, the management application 225 may increase thepower level for transmission to client device 125, given the mobility ofthis device and the potentially changing reception characteristics thatthis client device may experience.

For transmission to the access point 110 from the client devices 121,123, 125 and 127, the management application 225 can determine atransmission power level, based on the reception characteristics(including receptions by client devices 121, 123, 125 and 127 oftransmissions from other client devices), status characteristics,utilization characteristics and mobility characteristics, that aretransmitted by access point 110 to each respective client device. By wayof further examples, the client devices 121 and 127 may each adequatelyreceive transmissions from the access point 110. However, an analysis oftheir reception characteristics by access point 110 may reveal thatclient device 127 cannot detect transmissions from client device 121 andvice versa. In this scenario, the access point 110 may choose to boostthe transmission power of one or both of the client devices 121 and 127to avoid potential hidden terminal problems that could occur when clientdevice 121 and 127 attempt to transmit to access point 110. An analysisof reception characteristics and status characteristics by access point110 may also reveal that the client device 123 is easily detected byeach of the other devices and that it is running low on battery power.In response, the access point 110 can select a reduced transmissionpower level for the client device 123 that extends its battery life. Ananalysis of reception characteristics and mobility characteristics byaccess point 110 may reveal that the client device 125 is highly mobile.Rather than relying solely on reception characteristics, the accesspoint 110 selects a transmission power level for the client device 125that takes into consideration its possible movement about thetransmission range of the wireless network 10.

Also to manage power and transmissions, the management application 225is further operable to manage the protocol or protocols used incommunicating between the access point 110 and the client devices 121,123, 125 and 127 and power levels inherent in and associated therewith.In one mode of operation, management application 225 can selectivelyadjust one or more protocol parameters, such as the packet length, datarate, forward error correction, error detection, coding scheme, datapayload length, contention period, and back-off parameters used byaccess point 110 in communication with one or more of the client devices121, 123, 125 and 127, based on the analysis of the receptioncharacteristics, status characteristics, utilization characteristics,and mobility characteristics. In this fashion, the protocol parameterscan be adapted for power conservation and to minimize unnecessarytransmission power utilization based on the conditions of the network.These conditions for example include not only the mobility, utilization,status, and reception characteristics of a particular device, but themobility, utilization, status, and reception characteristics of aplurality of devices, and how well each client device receives otherclient devices.

For example, in the event that a client device, such as client device121, has difficulty detecting transmissions from client device 123,access point 110 can modify the protocol parameters so thattransmissions by client device 123 include more aggressive errorcorrecting codes, increased back-off times and/or smaller data payloadsor packet length to increase the chances that a packet will be receivedin the event of contention by client device 121. In addition, decreasingthe packet length can increase the frequency of acknowledgementstransmitted by access point 110. These acknowledgements can betransmitted at a power level sufficient to be heard by client device121. With increased back-off times, client device 121 has lessopportunity to create a potential contention.

In a further mode of operation, access point 110 and client devices 121,123, 125 and 127 can operate using a plurality of different, andpotentially complimentary, protocols having different protocolparameters. Access point 110 can likewise select a particular one of aplurality of protocols that suits the particular conditions present inthe wireless network 10, as determined based on an assessment ofutilization characteristics, status characteristics, mobilitycharacteristics and/or reception characteristics. For instance, anaccess point can select from 802.11(n), 802.11(g) or 802.11(b) protocolshaving different protocol parameters, data rates, etc, based on theparticular protocol best suited to accommodate the characteristics ofthe client devices 121, 123, 125 and 127 that are present.

It should be noted that these examples are merely illustrative of themany functions and features presented in the various embodiments of thepresent invention set forth more fully in conjunction with thedescription and claims that follow.

FIG. 2 presents a timing diagram of transmissions by the access point110 and the client devices 121 and 123 in accordance with an embodimentof the present invention. In particular, FIG. 2 shows exchanges betweenaccess point 110 and client device 121 and exchanges between accesspoint 110 and client device 123. While exchanges between the accesspoint 110 and two client devices are shown, the invention hereinlikewise applies for use with a greater number of client devices. Inthis diagram, transmissions such as data packets, acknowledgements andbeacons are represented by blocks whose relationship to the timing ofother events can illustrate a mode of operation, however, the durationsof these blocks are not shown to scale. The relative amplitude of theseblocks represents the power level of a particular transmission, withtaller blocks being transmitted at greater power and shorter blocksbeing transmitted at lower power.

Prior to the beginning of the time shown by FIG. 2, client device 121has generated first characteristics by evaluating transmissions, such asbeacons, test transmissions or routine on-going transmissions, from boththe access point 110 and other client devices, and further, byevaluating its own utilization, status and mobility. Likewise, clientdevice 123 has generated second characteristics by evaluatingtransmissions from both the access point 110 and other client devices,and its own utilization, status and mobility. Client device 121transmits, at a preset power level, transmission 130 to the access point110 that includes the first characteristics. Access point generates anacknowledgement 132 in response at a first power level, such as a highor full power level. Client device 123 transmits, at a preset powerlevel, transmission 134 to the access point 110 that includes the secondcharacteristics. Access point generates an acknowledgement 136 inresponse at the high power level.

The management application 225 of access point 110, having received thefirst characteristics from client device 121 and second characteristicsfrom client device 123. assesses both the first characteristics and thesecond characteristics and, based on the assessment, selects both asecond power level of the plurality of power levels for transmissions bythe access point 110 to the client device 121 and a third power level ofthe plurality of power levels for transmissions by the access point 110to the client device 123. Although not shown, the access point 110 mayselect an alternate protocol, based on such assessment, and coordinateswitch-over from that currently being used to the alternate protocol.

Assuming a protocol change is not warranted, the management application225 determines a selected power level for transmissions by the clientdevice 121 and a selected power level for transmissions by the clientdevice 123 and other possible protocol parameters that are sent,respectively, to clients devices 121 and 123 in transmissions 140 and144 that are acknowledged, respectively, by acknowledgements 142 and146.

After the transmission powers and protocol parameters for the accesspoint 110 and the client devices 121 and 123 are established, theoperating mode begins. In this example, the access point 110 transmitsat a highest power level for the periodic beacons 140. Transmissions toclient device 121, such as acknowledgement 154 are at a first reducedpower level that is sufficient for reception by client device 121.Transmissions to client device 123, such as transmissions 160 are at asecond reduced power level that is sufficient for reception by clientdevice 123. Periodic acknowledgements, such as acknowledgements 152 and156 are at a higher power level that can be heard by all of the clientdevices in the network. Transmissions 150 by client device 121 are atthe power level selected by access point 110 for this device based onthe characteristics of client device 121. Acknowledgements 162 by clientdevice 123 are transmitted at the power level selected by access point110 for client device 123 device based on the characteristics of thisdevice.

In this fashion, access point 110 transmits selected wirelesstransmissions, such as beacons 140 at a first power level, to reach bothclient devices 121 and 123 and potentially other devices that wish toassociate with wireless network 10. Other wireless transmissions, suchas periodic acknowledgements 152 and 156 by the access point 110, aresent at a second power level that is selected to support both deliveryof the packets to the client device 121 and detection of thesetransmissions by the client device 123, the first power level beinggreater than the second power level. In addition, wirelesstransmissions, such as transmissions 160 are sent at a third power levelselected to support receipt of the packets by client device 123 device,the second power level being greater than the third power level.

Alternatively, if circumstances warrant, the access point 110 couldchoose all of its transmissions other than the highest power beacons tobe tailored specifically for the client device 121 even though theclient devices 123 cannot hear such transmissions. To combat such hiddenterminal condition, the access point 110 commands the client device 121to transmit at a power level sufficient for the client device 123 todetect. With a protocol that requires at least periodic confirmation bythe client device 121 (e.g., interspersed acknowledge packets), eventhough the client device 121 cannot hear the access point 110, theclient device 123 will hear the periodic confirmation transmissions (orpayload transmissions from the client device 121), and thus determinethat the access point 110 is engaged. At the same time, the access point110 may determine that the client device 121 can hear transmissions bythe access point 110 at power levels only great enough to adequatelysupport the client device 123. Based on this determination, the accesspoint 110 might direct the client device 123 to transmit at a powerlevel only sufficient to adequately reach the access point 110 but notthe client device 121.

Of course, various other circumstances warrant various othertransmission power and protocol configurations. For example, if theaccess point 110 determines that transmissions from and to the clientdevice 121 can be selected such that they provide adequate performanceyet not be heard by the client device 123, the access point 110 mayadopt such power levels. Because the client device 123 has indicated anidle status, the access point 110 may accept any unexpected interferencefrom the client device 123 as it exits the idle status to transmitduring a communication exchange between the client device 121 and theaccess point 123. Thereafter, the access point 110 can change powerlevels to accommodate the both of the client devices 121 and 123 intheir active states. Or, instead of merely tolerating such unexpectedinterference, the access point 110 may employ a different protocoloperation or an entirely different protocol to accommodate suchcircumstances. An example of this would be for the access point 110 tocommand that the client device 123 only attempt transmissions from theidle state during a fixed period after a beacon and thereafter avoidcommunication exchanges with the client device 121 during such period.This change might be supported within the current protocol, or mightrequire a change from the current protocol to another. Similarly,instead of switching protocols, the access point 110 may choose tooperate two different protocols at the same time, by directing at leastone of the two of the client devices 121 and 123 to switch. Further, ifthe access point 110 detects that the client device 123 is plugged intoAC (Alternating Current) power, it may direct the client device 123 toalways transmit at a higher or highest power, while directing the clientdevice 121 (that may operate on limited battery power) to transmit atonly that necessary to reach the access point 110. Many othercircumstances and adaptation by the access point 110 to reduce overallunnecessary transmission power usage by one or more of the clientdevices 121 and 123 and the access point 110 itself are contemplated.

FIG. 3 presents a pictorial representation of a wireless network 10 thatshows examples of client devices and various modes of connection betweenaccess points and packet switched backbone network 101 in accordancewith an embodiment of the present invention. Packet switched backbonenetwork 101 includes wired data networks 230 such as a cable, fiber, orother wired or hybrid network for providing access, such as narrowband,broadband or enhanced broadband access to content that is local to wireddata network 230 or is otherwise accessed through Internet backbone 217.In particular, examples of wired data networks 230 include a publicswitched telephone network (PSTN), cable television network or privatenetwork that provides traditional plain old telephone service,narrowband data service, broadband data service, voice over internetprotocol (IP) telephony service, broadcast cable television service,video on demand service, IP television service, and/or other services.

Packet switched backbone network 101 further includes a terrestrialwireless data network 232 that includes a cellular telephone network,personal communications service (PCS), general packet radio service(GPRS), global system for mobile communications (GSM), or integrateddigital enhanced network (iDEN). These networks are capable of accessingwired data networks 230 through internet backbone 217 and for providingthe many of the services discussed in conjunction wired data networks230 in accordance with international wireless communications standardssuch as 2G, 2.5G and 3G.

Packet switched backbone network 101 also includes satellite datanetwork 234 for providing access to services such as satellite videoservices, satellite radio service, satellite telephone service andsatellite data service. In addition, packet switched backbone network101 includes other wireless data networks 236 such as a WiMAX network,ultra wideband network, edge network, Universal Mobile TelecommunicationSystem, etc., for providing an alternate medium for accessing any of theservices previously described.

Access points 211-213 provide access to WAN 101 through a wiredconnection to wired data networks 230. In addition, access point 213 iscapable of providing access to packet switched backbone network 101through wireless data networks 236. Set top box (STB) 214 includes thefunctionality of access points 211, 212, and/or 213 while furtherincluding optional access to terrestrial wireless data network 232, andsatellite data network 234. In particular, STB 214 optionally includesadditional functions and features directed toward the selection andprocessing of video content such as satellite, cable or IP videocontent. While the term “access point” and “set top box” have been usedseparately in the context of this discussion, the term “access point”shall include both the functionality and structure associated with a settop box, including but not limited to, STB 214.

A plurality of client devices are shown that include personal computers(PC) 203 and 206, wireless telephones 204 and 207, television (TV) 205,and wireless headphones 208. These client devices are merely examples ofthe wide range of client devices that can send data to and receive datafrom access points 211-213 and STB 214. While each of these clientdevices are shown pictorially as having integrated transceiver circuitryfor accessing a corresponding access point, an separate wirelessinterface device may likewise be coupled to the client module via a portsuch as a Universal Serial Bus (USB) port, Personal Computer Memory CardInternational Association (PCMCIA) Institute of Electrical andElectronics Engineers (IEEE) 488 parallel port, IEEE 1394 (Firewire)port, Infrared Data Association (IrDA) port, etc.

Access points 211-213 and STB 214 include a management application 225and personal computers (PC) 203 and 206, wireless telephones 204 and207, television (TV) 205, and wireless headphones 208, include clientassessment application 404 that allow these devices to implement thepower management method and structure in accordance with an embodimentof the present invention. Further discussion of these wireless networks,access points, client devices, including methods for use therewith willbe set forth in association with FIGS. 3-9 and the appended claims.

FIG. 4 presents a block diagram representation of an access point 300that can be used in wireless network 10 in accordance with an embodimentof the present invention. In particular, access point 300, such asaccess point 110, 211-213, STB 214, is presented. Access point 300includes a communication interface circuitry 308 for communicating withat least one packet switched backbone network 101. While a singleconnection is shown, in an embodiment of access point 300, such asaccess point 213 and/or STB 214, communication interface circuitry 308provides a plurality of interfaces that communicatively couples withpacket switched backbone network 101, such as the various networks shownin association with FIG. 2.

Access point 300 further includes access point transceiver circuitry302, operatively coupled to the communication interface circuitry 308,that manages communication by transmitting at a plurality of powerlevels and receives data over a wireless network 10, to and from aplurality of client devices, such as client devices 121, 123, 125, 127,PCs 203 and 206, wireless phones 204 and 207, TV 205 and wirelessheadphones 208. Access point 300 also includes memory circuitry 306, andprocessing circuitry 304 that controls communication flow between thecommunication interface circuitry 308 and the access point transceivercircuitry 302, and that implements management application 225.Management application 225 includes power logic 227 that selects thepower level of the plurality of power levels for periodic transmissionssuch as beacons, the transmission of data packets and the transmissionacknowledgements, based on the particular target or targets that accesspoint 300 wishes to reach with a particular transmission. In addition,management application 229 includes protocol logic 229 that selectseither particular protocol parameters, or particular protocols for usein communications with one or more of the client devices. Theseprotocols, protocol parameters, client device power levels andtransmission power levels for access point 300 are stored in memorycircuitry 306 and retrieved by processing circuitry 304 as needed.

The processing circuitry 304 may be a single processing device or aplurality of processing devices. Such a processing device may be, forexample, any one or more of a microprocessor, microcontroller, digitalsignal processor, field programmable gate array, programmable logicdevice, logic circuitry, state machine, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The memory circuitry 306 maybe a single memory device or a plurality of memory devices. Such amemory device may be read-only memory, random access memory, volatilememory, non-volatile memory, flash memory, static memory, dynamicmemory, optical or magnetic storage, and/or any device that storesdigital information. Note that when the processing circuitry 304implements one or more of its functions via a state machine, logiccircuitry, analog circuitry, and/or digital circuitry, the memorystoring the corresponding operational instructions may be embedded inthe circuitry comprising the state machine, logic circuit, analogcircuit, and/or digital circuit.

In an embodiment of the present invention, wireless network 10 conformsto at least one industry standard communication protocol such as 802.11,802.16, 802.15, Bluetooth, Advanced Mobile Phone Services (AMPS), GlobalSystem for Mobile Communication (GSM), and a General Packet RadioService (GPRS). Other protocols, either standard or proprietary, maylikewise be implemented within the scope of the present invention.

In operation, the management application 225 receives receptioncharacteristics, status characteristics, mobility characteristics andutilization characteristics from at least one of the plurality of clientdevices. The reception characteristics includes, for example, point topoint reception parameters such as the strength of signals received byat least one of the plurality of client devices from other devices overthe wireless link. Based on at least some of the receptioncharacteristics, status characteristics, mobility characteristics andutilization characteristics, the management application 225 selectstransmission power levels for itself and for each of the plurality ofclient devices, and transmits corresponding control signals to theplurality of client devices, directing transmission power adjustment tothe selected power levels. Further details, including several optionalfeatures of management application 225 are presented in association withFIG. 6.

Communication interface circuitry 308 and selected functions of APtransceiver circuitry 302 can be implemented in hardware, firmware orsoftware. Other functions of transceiver circuitry 302 are implementedin analog RF (Radio Frequency) circuitry as will be understood by oneskilled in the art when presented the disclosure herein. Whenimplemented in software, the operational instructions used to implementthe functions and features of these devices can also be implemented onprocessing circuitry 304 and stored in memory circuitry 306.

In operation, access point 300 communicates with each client device in apoint-to-point manner. To transmit data, access point 300 generates adata packet that is formatted based the selected protocol of wirelessnetwork 10. In particular, communication interface circuitry 308produces data payloads based on data received from packet switchedbackbone network 101. Other control information and data including theselected power levels and protocol parameters destined for the clientdevices of wireless network 10 are derived from power the managementapplication 225 of the processing circuitry 304.

AP transceiver circuitry 302 modulates the data, up-converts themodulated data to produce an RF signal of the wireless network 10. In anembodiment of the present invention, the AP transceiver circuitry 302transmits at one of a plurality of power levels, as determined bymanagement application 225. As one of average skill in the art willappreciate, if the access point 300 operates based on a carrier sensemultiple access with collision avoidance (CSMA/CA), when access point300 transmits data, each client device in communication with wirelessnetwork 10 may receive the RF signal, but only the client that isaddressed, i.e., a target client device, will process the RF signal torecapture the packet.

AP transceiver circuitry 302 is further operable to receive signals fromthe plurality of client devices over wireless network 10. In thisinstance, transceiver circuitry 302 receives an RF signal, down-convertsthe RF signal to a base-band signal and demodulates the base-band signalto recapture a packet of data. In particular, data payloads destined forpacket switched backbone network 101 are provided to communicationinterface circuitry 308 to be formatted in accordance with the protocolused by packet switched backbone network 101. Other control informationand data including the selected reception characteristics received fromthe client devices of wireless network 10 are provided to managementapplication 225 of processing circuitry 304.

FIG. 5 presents a block diagram representation of a client device 400that can be used in wireless network 10 in accordance with an embodimentof the present invention. A client device 400 is presented, such asclient devices 121, 123, 125, 127, PCs 203 and 206, wireless phones 204and 207, TV 205 and wireless headphones 208. In particular, clientdevice 400 includes a client transceiver circuitry 402 that transmitsand receives data over wireless network 10, that operates in a similarfashion to access point transceiver circuitry 402. However, clienttransceiver circuitry 402 is operable to transmit at a selected powerlevel, received from access point 300.

Client device 400 includes memory circuitry 408, and processingcircuitry 406 that implements client assessment application 404 andclient application 410. The processing circuitry 406 may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, microcontroller, digitalsignal processor, field programmable gate array, programmable logicdevice, logic circuitry, state machine, analog circuitry, digitalcircuitry, and/or any device that manipulates signals (analog and/ordigital) based on operational instructions. The memory circuitry 408 maybe a single memory device or a plurality of memory devices. Such amemory device may be read-only memory, random access memory, volatilememory, non-volatile memory, flash memory, static memory, dynamicmemory, and/or any device that stores digital information. Note thatwhen the processing circuitry 406 implements one or more of itsfunctions via a state machine, logic circuitry, analog circuitry, and/ordigital circuitry, the memory storing the corresponding operationalinstruction will be embedded in the circuitry comprising the statemachine, logic circuit, analog circuit, and/or digital circuit.

Further, client device 400 includes a client assessment application 404,operably coupled to the client transceiver circuitry 402, that assessessignals received from other devices, including the access point andother client devices, over the wireless network 10. In response, clientassessment application 404 generates reception characteristics andtransmits the reception characteristics over the wireless link to accesspoint 300.

In operation, the client assessment application 404 includes operationalinstructions that cause processing circuitry 406 to transfer data andsignals to and from client transceiver circuitry 402; to assess signals438 received from other devices, including other client devices, overthe wireless link; and to generate reception characteristics 436. In onemode of operation, client assessment application calculates a measure ofsignal strength, such as RSSI for each of the other devices and formatsthis information as reception characteristics 436 for transmission tomanagement application 225. Further details, including several optionalfeatures of client assessment application 404 are presented inassociation with FIG. 5.

Client application 410 includes the prime functions of the deviceitself, (e.g. a television, telephones, personal computer, headphones,etc.) Selected data packets transmitted to and wide area networkoriginate 101 from data received from client application 410. Inaddition, data packets received from packet switched backbone network101 are passed to client application 410.

Selected functions of client transceiver circuitry 402 can beimplemented in hardware, firmware or software. Other functions of clienttransceiver circuitry 402 are implemented in analog RF circuitry as willbe understood by one skilled in the art when presented the disclosureherein. When implemented in software, the operation instructions used toimplement the functions and features of these devices can be implementedon processing circuitry 406 and stored in memory circuitry 408.

In an embodiment of the present invention, one or more components ofclient transceiver circuitry 402, processing circuitry 406 and memorycircuitry 408 are implemented on an integrated circuit.

FIG. 6 presents a block diagram representation of a client device 400′with optional GPS circuitry 416 and power source regulation circuitry420 in accordance with an embodiment of the present invention. Clientdevice 400′ can be used in place of client device 400 in any of theapplications disclosed herein. In particular, a client assessmentapplication 404 includes operational instructions that cause processingcircuitry 406 to support the management application 225 of the accesspoint 300. In particular, the client assessment application 404 isoperably coupled to power source regulation circuitry 420 to monitor thecharging of optional battery pack 422, monitor the charge used bybattery pack 422, to determine the remaining charge on battery pack 422and whether the optional external power source 424 is currentlyconnected.

The client assessment application 404 includes operational instructionsthat cause processing circuitry 406 to generate battery life data 432and transmit such status characteristics over the wireless network 10via client transceiver circuitry 402. In one mode of operation, clientassessment application 404 generates and transmits further statuscharacteristics such as estimated remaining battery life. For instance,battery life data 432 can indicate the client device 400′ is coupled toexternal power source 424, an estimated battery life for one or moreselected power levels, an estimated battery life for one or more codingschemes, an estimated battery life battery life for one or more possibledata rates, an estimated battery life based on an estimated channelusage, an estimated battery life battery life based on an estimate ofrequired deterministic bandwidth, and an estimated battery life based onan estimate of non-deterministic bandwidth, or other estimates ofbattery life based on further operational parameters of client device400′. Also as mentioned previously, other types of statuscharacteristics can be generated pursuant to the client assessmentapplication 404 and communicated to the management application runningon the access point device 110.

Utilization characteristics can be similarly collected and communicated.For example, utilization characteristics may be retrieved directly fromthe current client application(s) or from the memory 408. Utilizationcharacteristics retrieved from the memory may have originated, forexample, based on: 1) prior interaction with or monitoring of the clientapplication 410; 2) user input; and 3) preset values.

The client assessment application 404 also causes the processingcircuitry 406 to generate and transmit mobility characteristics 434 overthe wireless link 434 via the client transceiver circuitry 402. GPSmodule 416 provides geographical data 418 such as GPS coordinates,scalar and/or vector velocities, accelerations, etc. In addition to suchgeographical coordinate data 418, mobility module can generate mobilitycharacteristics 434 that includes a mobility factor indicative ofwhether the client device is in a stationary condition, the clientdevice is in a low mobility condition such as a laptop computer thatshifts slightly on a table in a coffee shop, or whether the clientdevice is in a high mobility condition, such as in a car or other mobileenvironment. This additional mobility characteristics 434 can beassociated with a type of a device, e.g. a laptop computer may have alow mobility rating, a wireless transceiver circuitry mounted in avehicle may have a medium mobility rating, a desktop computer may have astationary mobility rating, etc. Further the mobility factor can be userselected based on the particular conditions. In addition, the mobilityfactor can be derived based on assessing a scalar or vector velocityfrom GPS module 416 and/or changes in geographical coordinate data 418over time, and comparing the velocity to one of a plurality of mobilitythresholds.

When generated and transmitted to management application 225, batterylife data 432, utilization characteristics 439, mobility characteristics434, and other status characteristics can further be used by managementapplication 225 for determining a selected power level for client device400′, for access point 300, and for other client devices of wirelessnetwork 10, and for determining either a particular protocol or protocolparameters used by client device 400′ in communications with accesspoint 300. When received, selected power level 462 and protocolparameter 464 can be used to generate the transmissions by client device400′ to access point 300.

FIG. 7 presents a block diagram representation of an access point 300′with optional AP assessment application 225 in accordance with anembodiment of the present invention. An access point 300′ is presentedthat includes many common elements of access point 300, referred to bycommon reference numerals. In addition, the access point 300′ includesan AP assessment application 226 that includes operational instructions,that cause the processing circuitry 304 to assess signals 438 receivedfrom the plurality of client devices, such as client device 400, overthe wireless network 10. The assessed strength of signals 438 can alsobe used by management application 225 to determine the selected powerlevel the plurality of client devices of wireless network 10. Accesspoint 300′ may be used in any of the applications discussed inconjunction with access point 300.

In particular, access point assessment application 226 assesses signals438 received from the plurality of client devices based upon a signalstrength criteria such as RSSI, a signal to noise ratio (SNR), a noiseparameter, or an amount of bit errors, and a bit error rate (BER) ofdata received from the particular client device.

In a test mode of operation, the access point assessment application 226is operable to generate a test packet such as an echo packet that istransmitted to the client device where a reply packet is transmitted andreceived back by access point 300. The number of bit errors or the BERfor this particular packet can be calculated by comparing the receiveddata to the data that was transmitted. All other client devices that donot participate in the exchange, listen and generate receptioncharacteristics for the access point assessment application 226.

In a further “sniffing” mode of operation, the access point assessmentapplication 226 receives reception characteristics generated by thevarious client devices based on normal, ongoing packets exchanges withthe access point. For example, reception characteristics might comprisean error detecting code such as a linear block code, convolutional codeor error correcting code can be used to determine the number of biterrors in the received data, within the coding limit of the particularcode use. For instance, a (24,12) Golay code with optional CRC bit coulddetect up to 4 errors in a 24 bit coded word before the coding limit wasreached.

The management application 225 assesses the received receptioncharacteristics 436, mobility characteristics 434, utilizationcharacteristics 439 and battery life data 432. Optional assessedstrength of signals are received from access point assessmentapplication 226. Although not shown, other types of statuscharacteristics and are also received and assessed by the managementapplication 225.

The management application 225 implements a plurality of powermanagement rules, based on the reception characteristics 436 (includingthe assessed strength of signals), the mobility characteristics 434,utilization characteristics, battery life data 432 and other statuscharacteristics. The power management rules generate a selected powerlevel to be used by the access point 300 and a selected power level 462to be used by one, all or a group of ones of a plurality of clientdevices, such as client device 400. Upon receiving a correspondingcontrol instruction from the management application 225, any such clientdevice responds adjusting the transmission power to that selected.

In operation, the access point 300′, through transceiver circuitry 302,is capable of transmitting at a selected power level that is based onfactors such as the type of transmission, the reception characteristics,status characteristics, utilization characteristics, mobilitycharacteristics, and the particular target device for the transmission.For instance, access point 300′ can transmit periodic beacons at a highpower level that include information such as a service set identifier(SSID) and network name. These beacons are used to support newassociations with client devices that enter the proximity of accesspoint 300′ or that otherwise become active within this proximity.Reception characteristics relating to how well client devices, such asthe client devices 121, 123, 125, 127, 400 and 400′, receive thesebeacon transmissions can be generated by the client assessmentapplications 404 of these client devices and transmitted back to theaccess point. In response, management application 225 determines acustomized power level for the access point to transmit to each clientdevice that can be reduced from the maximum power output, but thatprovides sufficient power to be received by that particular clientdevice. In addition, management application 225 determines anintermediate power level that is sufficient to be received by all of theclient devices that are currently associated with access point 300′.Specific packets, such as all acknowledgements (ACKs), every other ACK,every nth ACK etc., all data packets, occasional data packets, etc. aretransmitted by the access point 300′ at the intermediate power levelthat will reach all of the associated client devices, with the remainingpackets transmitted at the power level that is customized for theparticular client device 121, 123, 125, 127, 400 or 400′ to which thepackets are addressed.

By way of further example, the power level generation module can,through operation of the power management rules, determine which of theclient devices 400 are not being heard by other client devices. Inresponse, power level generation module can establish a selected powerlevel 462 for such client devices 400 to optionally boost thetransmission power so that they will be heard by some or all of theremaining client devices. In addition, power level generation module canreduce the power generated by a client device 400 that is generating astronger than necessary signal for being heard by the remaining clientdevices.

Management application 225 is further operable to manage the protocol orprotocols used in communicating between the access point 300′ and theclient devices associated with access point 300′ over wireless network10. In one mode of operation, management application 225 can selectivelyadjust one or more protocol parameters, such as the packet length, datarate, forward error correction, error detection, coding scheme, datapayload length, contention period, and back-off parameters used byaccess point 300′ in communication with one or more of the clientdevices 121, 123, 125, 127, 400 and/or 400′ based on the analysis of thereception characteristics, status characteristics, utilizationcharacteristics, and mobility characteristics. In this fashion, theprotocol parameters can optionally be adapted based on the conditions ofthe network, including not only the mobility, utilization, status, andreception characteristics of a particular device, but the mobility,utilization, status, and reception characteristics of a plurality ofother devices, including how well each client device receives otherclient devices.

For example, in the event that a first client device has difficultydetecting transmissions from a second client device, access point 300′can modify the protocol parameters so that transmissions by the secondclient device include more aggressive error correcting codes, increasedback-off times and/or smaller data payloads or packet length to increasethe chances that a packet will be received in the event of contention bythe first client device. In addition, decreasing the packet length canincrease the frequency of acknowledgements transmitted by access point300′. These acknowledgements can be transmitted at a power levelsufficient to be heard by the first client device. With increasedback-off times, first client device is less likely to create a potentialcontention.

In a further mode of operation, access point 300′ and its associatedclient devices can operate using a plurality of different, andpotentially complimentary, protocols having different protocolparameters. Access point 300′ can likewise select a particular one of aplurality of protocols that suits the particular conditions present inthe wireless network 10, as determined based on an assessment ofutilization characteristics, status characteristics, mobilitycharacteristics and/or reception characteristics. For instance, anaccess point can select from 802.11(n), 802.11(g) or 802.11(b) protocolshaving different protocol parameters, data rates, etc, based on theparticular protocol best suited to accommodate the characteristics ofthe client devices that are present.

In an embodiment of the present invention, one or more components ofcommunication interface circuitry 308, access point transceivercircuitry 302, memory circuitry 306 and processing circuitry 304 areimplemented on an integrated circuit.

FIG. 8 presents a pictorial representation of a wireless network 10 inaccordance with an embodiment of the present invention that provides amanagement application 225 in one of a plurality of terminals. Awireless network 10 includes terminals 400, 401 and 402 that are eachcapable of sending and receiving data from the other terminals over awireless link.

Terminal 400 includes a management application 225 and terminals 400 and402 include a client assessment application 404 that allows theselection of transmit power levels to promote effective communication,while reducing the power consumption of terminals. Each of the terminals400, 401 and 402 are operable to assess the signals received from otherdevices over the wireless link. Terminals 401 and 402 generate data suchas reception characteristics based on the assessed signals, battery lifedata based on estimates of power consumption, and other status,utilization and mobility characteristics based indicating how likely thesignal strengths for a particular terminal may change due to movement,how it is being used and its other anticipated current, estimated oranticipated conditions.

Terminals 401 and 402 transmit these data over the wireless link toterminal 400. Terminal 400, determines a selected power level andparticular protocols or protocol parameters for itself and for eachother terminal, based on the data that it receives for each device, andtransmits the selected power levels and protocol parameter(s) back toeach corresponding device. The terminals 401 and 402 can then transmitat a power level and with a protocol that takes advantage of theirparticular circumstances, including their status in the overall wirelessnetwork 10, and based on the positions and properties of the otherterminals that are present.

In operation, terminal 400, while not performing the specific functionsof an access point, is capable of performing other features andfunctions of either access point 300 or access point 300′ discussedherein. In addition, terminals 401, while not necessarily performing thefunctions of a client application, are capable of performing otherfeatures and functions of either client device 400 or client device 400′discussed herein.

In another mode, all parameters are exchanged between every wirelessterminal and the access point so that each can independently orcooperatively make transmission power control decisions.

For instance, a communication network such as wireless network 10 caninclude a first device such as terminal 400, having a first wirelesstransceiver that transmits at a plurality of power levels, a seconddevice, such as terminal 401 having a second wireless transceiver, and athird device, such as terminal 402 having a third wireless transceiver.The second device generates a first reception characteristic based on atleast one transmission from the third wireless transceiver, and thesecond device transmits the first reception characteristic to the firstwireless transceiver of the first device. The third device generates asecond reception characteristic based on at least one transmission fromthe second wireless transceiver, and the third device transmits thesecond reception characteristic to the first wireless transceiver of thefirst device. The transmission from the third wireless transceiver cancomprises either a portion of an ongoing data exchange or a portion of atest message.

The first device, based on the first reception characteristic, selects afirst power level of the plurality of power levels for transmissions bythe first transceiver circuitry to the third transceiver circuitry. Thefirst device, based on the second reception characteristic, selects asecond power level of the plurality of power levels for transmissions bythe first transceiver circuitry to the second transceiver circuitry, andthe first power level is greater than the second power level.

In another mode of operation, the first device is further operable toselect a first protocol parameter for transmissions by the firstwireless transceiver to the second device. The first device is furtheroperable to select a second protocol parameter for transmissions by thefirst wireless transceiver to the third device. This allows theprotocols as well as the power levels to be adapted to the particularconditions present in wireless network 10.

In a further mode, the first and second devices transmit mobilitycharacteristics, status characteristics, and utilization characteristicsto the first device. The first device assesses at least a portion of themobility, status and utilization characteristics along with thereception characteristic to generate the power levels for itself and forthe second and third devices and for the protocol parameters used bythese devices to format transmissions that are sent and to decodetransmissions that are received.

FIG. 9 presents a flowchart representation of a method that can be usedin a terminal, access point and/or an integrated circuit in accordancewith an embodiment of the present invention. In particular, a method ispresented for use in conjunction with one or more features and functionspresented in association with FIGS. 1-8. In step 500, receptioncharacteristics, mobility characteristics, utilization characteristics,and status characteristics are received from one or more client devicesover a wireless link. In step 502, the signals received from one or moreclient devices over the wireless link are assessed and local receptioncharacteristics is generated. Such signals are either test signals orpart of ongoing communication exchanges. In step 504, transmission powerlevels and protocol parameters are determined for each of the clientdevices and for local use based on any part or all of the locallygenerated reception characteristics and the received mobility,reception, utilization, and status characteristics. In step 506, thelocal transmission power and protocol is adjusted, if needed, andcommands requesting transmission power and protocol adjustments are sentto each of the client devices as needed. This method is well suited forbeing implemented as operational instructions that are stored in amemory such as memory circuitry 306 and implemented using processingcircuitry such as processing circuitry 304.

For example, the status characteristics related to battery life mightindicate one or more of the following: whether the client device iscoupled to an external power source; the battery life for at least oneselected power level; the battery life for at least one coding scheme;the battery life for at least one data rate; the battery life based onan estimated channel usage; the battery life based on an estimate ofrequired deterministic bandwidth; and the battery life based on anestimate of non-deterministic bandwidth. The mobility characteristicsmight indicate, for example, one or more of the following: the clientdevice is in a stationary condition; the client device is in a lowmobility condition; the client device is in a high mobility condition;and a geographical coordinate of the client device.

The reception characteristics such as the assessment signal strengthmight include, for example, one or more of: a received signal strengthindicator (RSSI); a signal to noise ratio; a noise parameter; an amountof bit errors; and a bit error rate (BER). In one mode of operation, atest packet such as an echo packet is transmitted to the client devicewhere a reply packet is transmitted and received back. The number of biterrors or the BER for this particular packet can be calculated bycomparing the received data to the data that was transmitted.

In further mode of operation, received data is assessed based on thepayload of normal packets that are received. For instance, an errordetecting code such as a linear block code, convolutional code or errorcorrecting code can be used to determine the number of bit errors in thereceived data, within the coding limit of the particular code use. Forinstance, a (24,12) Golay code with optional CRC bit could detect up to4 errors in a 24 bit coded word before the coding limit was reached.

In one mode of operation, step 504 implements a plurality of powermanagement rules, based on the reception characteristics, and optionallythe mobility characteristics, battery life data and the assessedstrength of signals. These power management rules generate a selectedpower level for an access point based on factors such as the type oftransmission, the reception characteristics, status characteristics,utilization characteristics, mobility characteristics, and theparticular target device for the transmission. For example, the accesspoint can transmit periodic beacons at a high power level that includeinformation such as a service set identifier (SSID) and network name.These beacons are used to support new associations with client devicesthat enter the proximity of the access point or that otherwise becomeactive within this proximity. Reception characteristics relating to howwell the client devices receive these beacon transmissions can begenerated by the client devices and transmitted back to the accesspoint. In response, the access point determines a customized power levelfor transmissions to each client device that can be reduced from themaximum power output, but that provides sufficient power to be receivedby that particular client device. In addition, the access pointdetermines an intermediate power level that is sufficient to be receivedby all of the client devices that are currently associated with accesspoint. Specific packets, such as all acknowledgements (ACKs), everyother ACK, every nth ACK etc., all data packets, occasional datapackets, etc. are transmitted by the access point at the intermediatepower level that will reach all of the associated client devices, withthe remaining packets transmitted at the power level that is customizedfor the particular client device to which the packets are addressed.

In a further mode of operation, these power management rules establish aselected power level for a plurality of client devices, that areequipped to receive the selected power level and to set the selectedpower level accordingly. The selected power levels are transmitted tothe corresponding client devices. The selected power level for eachclient device can be a discrete variable that takes on one of a finitenumber of values. For example, through operation of the power managementrules, the method can determine which of the client devices are notbeing heard by other client devices. In response, a selected power levelcan be established for such client devices to optionally boost thetransmission power so that they will be heard by some or all of theremaining client devices. In addition, power management rules can reducethe power generated by a client device that is generating a strongerthan necessary signal for being heard by the remaining client devices.

In a further example, an analysis of reception characteristics andbattery life data may reveal that a client device is easily detected byeach of the other devices and that it is running low on battery power.In response, a reduced power level can be selected for that device toextend its battery life.

In another example, an analysis of reception characteristics andmobility characteristics may reveal that a client device is highlymobile. Rather than relying solely on reception characteristics, thepower management rules select a power level for an access point orclient device that takes into consideration the client device's possiblemovement.

In addition, the protocol or protocols used in communicating betweendevices of the wireless network are adapted to the particularcharacteristics of the access point and the client devices. In one modeof operation, the method can selectively adjust one or more protocolparameters, such as the packet length, data rate, forward errorcorrection, error detection, coding scheme, data payload length,contention period, and back-off parameters used in communication betweendevices, based on the analysis of information, such as the receptioncharacteristics, status characteristics, utilization characteristics,and mobility characteristics of these devices. In this fashion, theprotocol parameters can optionally be adapted based on the conditions ofthe network, including not only the mobility, utilization, status, andreception characteristics of a particular device, but the mobility,utilization, status, and reception characteristics of a plurality ofdevices, including how well each device receives transmissions fromother devices.

In this fashion, the method can include selecting a first power level ofthe plurality of power levels for periodic transmissions by an accesspoint; receiving a first plurality of characteristics relating to anevaluation by a first client device of transmissions received by thefirst client device from both the access point and a second clientdevice; receiving a second plurality of characteristics relating to anevaluation by the second client device of transmissions received by thesecond client device from both the access point and the first clientdevice; and assessing both the first plurality of characteristics andthe second plurality of characteristics and, based on the assessment,selecting both a second power level of the plurality of power levels fortransmissions by the access point to the first client device and a thirdpower level of the plurality of power levels for transmissions by theaccess point to the second client device, and the first power level isgreater that the second power level, while the second power level isgreater than the third power level.

FIG. 10 presents a flowchart representation of a method that can be usedin a terminal, client device and/or an integrated circuit in accordancewith an embodiment of the present invention. In particular, a method ispresented for use in conjunction with one or more features and functionspresented in association with FIGS. 1-9. In step 600, signals receivedfrom other devices over a wireless link by a client device are gatheredand assessed along with battery status, device operating status, clientapplication status and anticipated communication requirements andmobility information. In step 602, based on such gathering andassessment, reception, status, utilization and mobility characteristicsare generated. In step 604, such generated characteristics aretransmitted over the wireless link. In step 606, in response to thetransmission in step 604, a command requesting a transmission powerlevel and protocol adjustment is received over the wireless link. Instep 608, data is transmitted over the wireless link in accordance withthe request at the selected power level and protocol. This method iswell suited for being implemented as operational instructions that arestored in a memory such as memory circuitry 408 and implemented usingprocessing circuitry such as processing circuitry 406.

For example, the status characteristics such as battery life data canindicate one or more of the following: whether a device such as a clientdevice is coupled to an external power source, the battery life for atleast one selected power level, the battery life for at least one codingscheme, the battery life for at least one data rate, the battery lifebased on an estimated channel usage, the battery life based on anestimate of required deterministic bandwidth, and the battery life basedon an estimate of non-deterministic bandwidth. The mobilitycharacteristics can indicates one or more of the following: the clientdevice is in a stationary condition, the client device is in a lowmobility condition, the client device is in a high mobility condition,and a geographical coordinate of the client device.

The assessment signal strength can include one or more of: a receivedsignal strength indicator (RSSI), a signal to noise ratio, a noiseparameter, an amount of bit errors, and a bit error rate (BER). In onemode of operation, a test packet such as an echo packet is transmittedto the client device where a reply packet is transmitted and receivedback. The number of bit errors or the BER for this particular packet canbe calculated by comparing the received data to the data that wastransmitted.

In further mode of operation, received data is assessed based on thepayload of normal packets that are received. For instance, an errordetecting code such as a linear block code, convolutional code or errorcorrecting code can be used to determine the number of bit errors in thereceived data, within the coding limit of the particular code use. Forinstance, a (24,12) Golay code with optional CRC bit could detect up to4 errors in a 24 bit coded word before the coding limit was reached.

In one mode of operation, a device, such as a client device, terminal oraccess point, implements a plurality power management rules, based onthe reception characteristics, and optionally the mobilitycharacteristics, battery life data and the assessed strength of signals.These power management rules generate a selected power level for thehost terminal, access point of client device and for a plurality ofclient devices, that are equipped to receive a selected power level andto set the selected power level accordingly. The selected power levelsare transmitted to the corresponding client devices. The selected powerlevel for each client device can be a discrete variable that takes onone of a finite number of values.

For example, through operation of the power management rules, the methodcan determine which of the client devices are not being heard by otherclient devices. In response, a selected power level can be establishedfor such client devices to optionally boost the transmission power sothat they will be heard by some or all of the remaining client devices.In addition, power management rules can reduce the power generated by aclient device that is generating a stronger than necessary signal forbeing heard by the remaining client devices.

In a further example, an analysis of reception characteristics andbattery life data may reveal that a client device is easily detected byeach of the other devices and that it is running low on battery power.In response, a reduced power level can be selected for that device toextend its battery life, with or without one or both of: a) switchingthe low power device to another protocol or otherwise adapting itscurrent protocol in accommodation; and b) switching all other devices toanother protocol or otherwise adapting their current protocol inaccommodation

In another example, an analysis of reception characteristics andmobility characteristics may reveal that a client device is highlymobile. Rather than relying solely on reception characteristics, thepower management rules select a power level for this client device thattakes into consideration its possible movement.

In this fashion, the present invention can include a the method for usein a first client device that, along with at least a second clientdevice, wirelessly communicates with and a packet switched backbonenetwork via an access point. Periodic transmissions by the access pointat first power level of the plurality of power levels are received.Transmissions received from both the access point and the second clientdevice are evaluated and a first plurality of characteristics relatingto the evaluation by the first client device are transmitted to theaccess point. A transmission is received from the access point at asecond power level of the plurality of power levels that is based on anassessment of both the first plurality of characteristics and a secondplurality of characteristics from the second client device, wherein thefirst power level is greater that the second power level, and thetransmission contains a selected power level and one or more protocolparameters for transmissions by the first client device. In response theclient device transmits at the selected power level and in accordancewith the protocol parameter(s).

As one of ordinary skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term and/or relativitybetween items. Such an industry-accepted tolerance ranges from less thanone percent to twenty percent and corresponds to, but is not limited to,component values, integrated circuit process variations, temperaturevariations, rise and fall times, and/or thermal noise. Such relativitybetween items ranges from a difference of a few percent to magnitudedifferences. As one of ordinary skill in the art will furtherappreciate, the term “operably coupled”, as may be used herein, includesdirect coupling and indirect coupling via another component, element,circuit, or module where, for indirect coupling, the interveningcomponent, element, circuit, or module does not modify the informationof a signal but may adjust its current level, voltage level, and/orpower level. As one of ordinary skill in the art will also appreciate,inferred coupling (i.e., where one element is coupled to another elementby inference) includes direct and indirect coupling between two elementsin the same manner as “operably coupled”. As one of ordinary skill inthe art will further appreciate, the term “compares favorably”, as maybe used herein, indicates that a comparison between two or moreelements, items, signals, etc., provides a desired relationship. Forexample, when the desired relationship is that signal 1 has a greatermagnitude than signal 2, a favorable comparison may be achieved when themagnitude of signal 1 is greater than that of signal 2 or when themagnitude of signal 2 is less than that of signal 1.

In preferred embodiments, the various circuit components are implementedusing 0.35 micron or smaller CMOS technology. Provided however thatother circuit technologies including other transistor, diode andresistive logic, both integrated or non-integrated, may be used withinthe broad scope of the present invention. Likewise, various embodimentsdescribed herein can also be implemented as software programs running ona computer processor. It should also be noted that the softwareimplementations of the present invention can be stored on a tangiblestorage medium such as a magnetic or optical disk, read-only memory orrandom access memory and also be produced as an article of manufacture.

As the term module is used in the description of the various embodimentsof the present invention, a module includes a functional block that isimplemented in hardware, software, and/or firmware that performs one ormodule functions such as the processing of an input signal to produce anoutput signal. As used herein, a module may contain submodules thatthemselves are modules.

Thus, there has been described herein an apparatus and method, as wellas several embodiments including a preferred embodiment, forimplementing a wireless network, access point, client device, integratedcircuit. Various embodiments of the present invention herein-describedhave features that distinguish the present invention from the prior art.

It will be apparent to those skilled in the art that the disclosedinvention may be modified in numerous ways and may assume manyembodiments other than the preferred forms specifically set out anddescribed above. Accordingly, it is intended by the appended claims tocover all modifications of the invention which fall within the truespirit and scope of the invention.

1. A method for use in an access point that wirelessly couples a firstclient device and a second client device to a backbone network, themethod comprising: selecting a first power level for periodictransmissions by the access point; receiving a first plurality ofcharacteristics relating to an evaluation by the first client device oftransmissions received by the first client device from both the accesspoint and the second client device; receiving a second plurality ofcharacteristics relating to an evaluation by the second client device oftransmissions received by the second client device from both the accesspoint and the first client device; and assessing both the firstplurality of characteristics and the second plurality of characteristicsand, based on the assessment, selecting a plurality of customized powerlevels for transmissions by the access point to the first client deviceand the second client device.
 2. The method of claim 1, wherein thetransmissions evaluated by the first client device comprise at least aportion of an ongoing data exchange.
 3. The method of claim 1, whereinthe transmissions evaluated by the first client device comprise at leastone test signal exchange.
 4. The method of claim 1, wherein the firstplurality of characteristics include mobility characteristics.
 5. Themethod of claim 1, wherein the first plurality of characteristicsinclude utilization characteristics.
 6. The method of claim 1, whereinthe first plurality of characteristics include status characteristics.7. The method of claim 1, wherein the step of assessing both the firstplurality of characteristics and the second plurality of characteristicsfurther includes selecting a first protocol parameter for transmissionsby the access point transceiver circuitry to the first clienttransceiver.
 8. A method for use in a first client device that, alongwith at least a second client device, wirelessly communicates with and abackbone network via an access point, the method comprising: receivingperiodic transmissions by the access point at first power level;evaluating transmissions received from both the access point and thesecond client device and transmitting to the access point a firstplurality of characteristics relating to the evaluation by the firstclient device; receiving a transmission from the access point thatcontains a selected power level for transmissions by the first clientdevice; and transmitting at the selected power level.
 9. The method ofclaim 8, wherein the transmissions evaluated by the first client devicecomprise at least a portion of an ongoing data exchange.
 10. The methodof claim 8, wherein the transmissions evaluated by the first clientdevice comprise at least one test signal exchange.
 11. The method ofclaim 8, wherein the first plurality of characteristics include mobilitycharacteristics.
 12. The method of claim 8, wherein the first pluralityof characteristics include utilization characteristics.
 13. The methodof claim 8, wherein the first plurality of characteristics includestatus characteristics.
 14. The method of claim 8, wherein the step ofreceiving a transmission from the access point further includesreceiving a first protocol parameter for transmissions received from theaccess point transceiver circuitry.
 15. A wireless communicationprotocol used by an access point to deliver first data packets to afirst wireless device and second data packets to a second wirelessdevice, the wireless communication protocol comprising: first wirelesstransmissions by the access point device at a first power leveltargeting both the first wireless device and the second wireless device;second wireless transmissions by the access point device at a secondpower level selected to support both delivery of the first data packetsto the first wireless device and detection of the second wirelesstransmissions by the second wireless device; and third wirelesstransmissions of at least the second data packets by the access pointdevice at a third power level selected to support receipt of the seconddata packets by the second wireless device.
 16. The wirelesscommunication protocol of claim 15, wherein the second wirelesstransmissions are in accordance with a first protocol parameter, thethird wireless transmissions are in accordance with a second protocolparameter, and the second protocol parameter is different from the firstprotocol parameter.